Recirc pump with a thermostatic valve issue?

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Dean45

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Hello all. Running a hybrid hot water heater. Using it as an excess solar energy dump as well by using the element when need. I am running the temp around 132 F now. The thermostatic valve I added is giving me 124 f

The amount of time and "coldness" of the water when the hot is opened is longer and colder than it was before. Noticeably as pointed out so elegantly by my wife. Is this by design? Does the orientation of the thermostatic valve make a difference?

Any thoughts/suggestions are appreciated.
 

jadnashua

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Without seeing a block diagram of what you have, it's hard to say.

The tempering valve may have stopped the passive circulation, and starting with cooler water will mean it will take longer to heat the pipes to the fixture. Depending on how long the runs are can make a difference. If you don't have a working check valve in the recirculation system, it won't work well, either.
 
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Dean45

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Without seeing a block diagram of what you have, it's hard to say.

The tempering valve may have stopped the passive circulation, and starting with cooler water will mean it will take longer to heat the pipes to the fixture. Depending on how long the runs are can make a difference. If you don't have a working check valve in the recirculation system, it won't work well, either.
That makes sense. Think having the recirc pump before the thermo valve instead of where is is after would make the difference? And where would the check valve need to be added to be effective.

Thanks for your help!
 

Jeff H Young

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So you had a working system that was perfect for how long? then you added a thermostatic valve and now you liked it better befor? put it back the way it was
 

Dean45

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So you had a working system that was perfect for how long? then you added a thermostatic valve and now you liked it better befor? put it back the way it was
Appreciate the snark. Reminds me of how forum discussions head down hill quickly. For the sake of brevity I did not include all of the info.

I added a hybrid hot water heater last year. I maintain a gas boiler with indirect HW tank. So I fire up the boiler in late December to late February. Since my new central heat pump is not as efficient in the deep winter in NY and I get some secondary heating of the finished basement when the boiler is on.

The hybrid provides cooling and dehumidifying as well as efficient hot water during the rest of the year. I have had solar for the past 8 years as well. I am trying to also use the hybrid as a solar dump and limit how much I am sending back to the grid.

So what I am trying to do is kick up the hw tank temp using either heat pump or element to use some of the excess electricity I am producing. But having twin 5 year old boys stops me from having that high temp water making it to any faucet.

Again pointing out the obvious was fun for you hopefully. I know I am a new member but have learned so much from the discussions here the last 5 years as a lurker.
 

jadnashua

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Without a check valve (note, some pumps may have one built-in so a separate one may not be needed), when you draw hot water, you're going to pull it from the normal hot supply line, and the return line (normally going into the cold inlet or the drain of the WH), assuming you have a dedicated return line. If you're using a system that utilizes the cold line as the return, then there's some sort of cross-over valve normally located at the furthest point or on multiple branches, depending on how the piping is laid out.

Without seeing what thermostatic valve you have or how it is all installed, hard to say what's the problem. Sometimes, just drawing it out will clear it up. The hot water needs a full loop from and back to the WH with a check valve and the pump in there somewhere.
 

Fitter30

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Thermostatic tempering valves need service at least once a year all depends how hard the water is. Need either a spare element or time to remove yours soak it in vineger long enough to clean it. Easier to have a spare element.
 

Jeff H Young

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dean 45 hard to figure out when you leave stuff out opening post not very clear
 

Dean45

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Without a check valve (note, some pumps may have one built-in so a separate one may not be needed), when you draw hot water, you're going to pull it from the normal hot supply line, and the return line (normally going into the cold inlet or the drain of the WH), assuming you have a dedicated return line. If you're using a system that utilizes the cold line as the return, then there's some sort of cross-over valve normally located at the furthest point or on multiple branches, depending on how the piping is laid out.

Without seeing what thermostatic valve you have or how it is all installed, hard to say what's the problem. Sometimes, just drawing it out will clear it up. The hot water needs a full loop from and back to the WH with a check valve and the pump in there somewher
So reading this and finding some other text online I realized my cold feed for the thermostatic valve it tee'd from the cold supply of the hot water tank. So as water is returned to the hot water tank it is entering the thermo valve instead of going into the tank. leaving me with a slug of cooler water that needs to pass when a hot side of faucet is opened. At least this is how I am understanding this.

Would a check valve in the cold line before the thermostatic valve prevent this constant cold water "trickle"? That would be a quick easy fix if so. Or do I need to find a cold supply from somewhere else? That would be a bit more of a challenge.

I know a diagram would help but doing it from memory might just confuse the issue.
 
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Dean45

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So reading this and finding some other text online I realized my cold feed for the thermostatic valve it tee'd from the cold supply of the hot water tank. So as water is returned to the hot water tank it is entering the thermo valve instead of going into the tank. leaving me with a slug of cooler water that needs to pass when a hot side of faucet is opened. At least this is how I am understanding this.

Would a check valve in the cold line before the thermostatic valve prevent this constant cold water "trickle"? That would be a quick easy fix if so. Or do I need to find a cold supply from somewhere else? That would be a bit more of a challenge.

I know a diagram would help but doing it from memory might just confuse the issue.
So I attached a few photos. I added the check valve on the horizontal cold feed after reading your suggestions. Did not seem to help. The recirc was installed before I put the hybrid in. The white tank is the original indirect hw tank. The boiler and expansion tank are to the right of the white tank.

I stripped out the thermo valve to see if the recirc it working on its own. It seems to be. So either this is a no go or I need to reposition pumps, checks, or feeds? Seems like more than I care to do. Any help appreciated.
 

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jadnashua

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Do you have a dedicated return line for the recirc, or are you using the cold line for that?

Sorry, I need a block diagram of what you have to try to figure out what's going on. Maybe someone else can decipher what's there.

You do need a check valve on the return line so you aren't trying to pull water from the hot supply and the return at the same time. IOW, when you are trying to use hot water, it must only be able to get it from the WH, not from any other path or the water will mix.
 
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